[Core] Move function tracing setup to util function (#4352)

vllm/utils.py

 import asyncio
+import datetime
 import enum
 import gc
 import glob
 import os
 import socket
 import subprocess
+import tempfile
+import threading
 import uuid
 import warnings
 from collections import defaultdict
@@ -18,7 +21,7 @@ import psutil
 import torch
 from packaging.version import Version, parse
 
-from vllm.logger import init_logger
+from vllm.logger import enable_trace_function_call, init_logger
 
 T = TypeVar("T")
 logger = init_logger(__name__)
@@ -607,3 +610,19 @@ def find_nccl_library():
             raise ValueError("NCCL only supports CUDA and ROCm backends.")
         logger.info(f"Found nccl from library {so_file}")
     return so_file
+
+
+def enable_trace_function_call_for_thread() -> None:
+    """Set up function tracing for the current thread,
+    if enabled via the VLLM_TRACE_FUNCTION environment variable
+    """
+
+    if int(os.getenv("VLLM_TRACE_FUNCTION", "0")):
+        tmp_dir = tempfile.gettempdir()
+        filename = (f"VLLM_TRACE_FUNCTION_for_process_{os.getpid()}"
+                    f"_thread_{threading.get_ident()}_"
+                    f"at_{datetime.datetime.now()}.log").replace(" ", "_")
+        log_path = os.path.join(tmp_dir, "vllm", get_vllm_instance_id(),
+                                filename)
+        os.makedirs(os.path.dirname(log_path), exist_ok=True)
+        enable_trace_function_call(log_path)

vllm/worker/worker_base.py

-import datetime
 import importlib
 import os
-import tempfile
-import threading
 from abc import ABC, abstractmethod
 from typing import Dict, List, Set, Tuple
 
-from vllm.logger import enable_trace_function_call, init_logger
+from vllm.logger import init_logger
 from vllm.lora.request import LoRARequest
 from vllm.sequence import SamplerOutput, SequenceGroupMetadata
-from vllm.utils import get_vllm_instance_id, update_environment_variables
+from vllm.utils import (enable_trace_function_call_for_thread,
+                        update_environment_variables)
 
 logger = init_logger(__name__)
 
@@ -128,15 +126,7 @@ class WorkerWrapperBase:
        function tracing if required.
         Arguments are passed to the worker class constructor.
         """
-        if int(os.getenv("VLLM_TRACE_FUNCTION", "0")):
-            tmp_dir = tempfile.gettempdir()
-            filename = (f"VLLM_TRACE_FUNCTION_for_process_{os.getpid()}"
-                        f"_thread_{threading.get_ident()}_"
-                        f"at_{datetime.datetime.now()}.log").replace(" ", "_")
-            log_path = os.path.join(tmp_dir, "vllm", get_vllm_instance_id(),
-                                    filename)
-            os.makedirs(os.path.dirname(log_path), exist_ok=True)
-            enable_trace_function_call(log_path)
+        enable_trace_function_call_for_thread()
 
         mod = importlib.import_module(self.worker_module_name)
         worker_class = getattr(mod, self.worker_class_name)